A man convicted of 159 sex offences on men has been branded ‘Britain’s most prolific rapist’.

Reynhard Sinaga, 36, was found guilty of targeting around 48 men outside clubs in Manchester and lured them back to his flat where he proceeded to drug and assault them, while filming the attacks.

Sinaga was already serving life with a minimum term of 20 years for offences he was convicted of in two earlier trials – which took place in summer 2018 and last spring.

But now, a judge has ruled his life sentence must include a minimum of 30 years in jail and lifted reporting restrictions, the BBC reported.

Across four separate trials, the Indonesian national was found guilty of 136 counts of rape, eight counts of attempted rape, 14 counts of sexual assault and one count of assault by penetration against a total of 48 victims.

At a sentencing today (January 6), judge Suzanne Goddard QC branded Singaga an ‘evil serial sexual predator’ who would ‘never be safe to be released’.

She added: “The true scale of your offending may never be known.”

According to the BBC, Sinaga would target men leaving nightclubs and bars outside Manchester clubs before taking them to his flat in Princess Street where he offered them a drink.

He then drugged his victims before assaulting them while they were unconscious. When the victims woke up, they had no recollection of what had happened.

In an earlier sentencing, the judge ruled that she was sure he had used some sort of date rape drug such as GHB.

Several of his victims said the ordeal had left them with serious mental health issues, with some developing suicidal thoughts.

Following his sentence, Ian Rushton, from the Crown Prosecution Service, said Sinaga was ‘the most prolific rapist in British legal history’ and possibly ‘in the world’.

"His extreme sense of sexual entitlement almost defies belief and he would no doubt still be adding to his staggering tally had he not been caught," he said.

Rushton added that Sinaga – who carried out his attacks over several years - took a ‘particular pleasure in preying on heterosexual men’.

Sinaga was caught in June 2017 when one victim – who regained consciousness while being assaulted – fought him off and called the police.

After police seized his phone, they found he had filmed each of his attacks – which added up to hundreds of hours of footage.

This led to the launch of one of the largest rape inquiries in British history.

Investigators were able to trace multiple victims from the videos using clues such as stolen phones, ID cards and watches.

Assistant Chief Constable Mabbs Hussain said: “We suspect he's offended over a period of 10 years.

"The information and evidence we are going from is largely from trophies that he's collected from the victims of his crimes."

His trial took place across 18 months and resulted in an unanimous guilty verdict.

Around 70 victims have been identified but police are appealing for people to come forward.

The student, who denied the charges, had claimed all the sexual activity was consensual and that each man had agreed to being filmed while pretending to be asleep.